1. Field of the Invention
The present invention relates generally to brake systems, and more specifically, to a system and method to inspect and correct brake shoe alignment of railcars.
2. Description of Related Art
Braking systems for railcars are well known in the art and are effective means to slow down or stop a railcar during transit. FIGS. 1 and 2 depict a conventional braking system for a railcar 10. Referring first to FIG. 1, reference numeral 10 generally designates a railcar having a frame chassis 12 which generally includes spaced frame rails 14 connected by bolster 16. Axles 18 accommodate rotatable wheels 20 and are journalled in frame rails 14 in a common manner.
Brake system 22 is connected to railcar 10 and serves to slow and/or stop the car in a common manner. Brake system 22 may be employed in the truck mounted fashion shown or may be employed in other brake system designs commonly known in the industry. System 22 as shown includes generally a power driven cylinder 24, slack adjuster 26, connecting linkages and levers 28, 30, and brake beams 32 which carry brake shoes 34. Brake shoes 34 are positioned adjacent to wheels 20 as shown in the drawings and serve to slow and/or stop the railcar 10 by friction.
Frame rails 14 each include guide channel parts 36. As shown in FIG. 2, each guide channel 36 is defined by top wall 38 and spaced bottom wall 40 to define a slot or channel 42. Typically, channel 36 are oriented at an oblique angle relative to the upper and lower edges of frame rails 14 as shown.
Each opposed brake beam 32 carries brake shoes 34, preferably of a fiber composite material. Brake shoes 34 are secured to brake head 44 of brake beams 32 as by mounting straps (not shown). Each brake beam 32 includes an end extension 46 located at each end of each beam. In the exemplary embodiment, end extension 46 is slidably fitted in channel part 36 and reciprocates within channel 42.
In the exemplary embodiment, end extension 46 is of a generally rectangular of polygonal cross-section, for example a polygonal cross-section is a generally rectangular cross-sectional configuration with noted exceptions. As shown, two of the opposite diagonal corners define oblique angle surfaces. The other two opposite diagonal corners define spaced parallel surfaces 48, 50 which are offset longitudinally from each other. Extension parts 46 are either fixedly secured to brake beams 32 or may be integrally formed as part of each beam.
FIG. 2 illustrates brake system 22 in an unbraked position with brake shoes 34 spaced from railcar wheels 20. In this position brake beams 32 are retracted with the centerline 60 of each guide channel 42 slightly offset from the center axis 62 of each wheel 20.
As depicted in FIG. 3, a common disadvantage associated with system 22 is the wear created on the brake shoes 34 after use. In the exemplary embodiment, the brake shoe 34 has greater wear on surface 301 at an upper surface area 303 when compared to the lower surface area 305. Thus, it should be understood that the shoes do not wear evenly, thereby creating different thicknesses T1, T2, which in turn causes rotation of the end extension as the end extension slides within guide channel 36, as depicted in FIGS. 4A and 4B.
It should be understood that having different shoe thicknesses could cause damage to the components of the railcar. Conventional methods to correct the above-discussed problems include the time consuming and expensive process of inspecting, discarding, and replacing the shoe 34 if uneven brake shoe wear exist.
Although great strides have been made in the area of systems and methods to inspect and replace railway braking shoes, many shortcomings remain.
While the system and method of use of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present application as defined by the appended claims.